Broadband antenna

Abstract

A broadband antenna including an antenna body, a ground plane, and a bandwidth adjustment portion is described. The bandwidth adjustment portion, formed by at least one capacitor, is connected between the antenna body and the ground plane. The bandwidth adjustment portion is formed by more than one capacitor connected in series. Also, in another situation, the bandwidth adjustment portion can be formed by more than one capacitor connected in parallel.

1. A broadband antenna, comprising:
 an antenna body, formed by a first conductor having an open end, a second conductor, and a third conductor, wherein the second conductor has a first end connected to the first conductor, and the third conductor has a first end connected to the first conductor; 
 a feed-in point, connected to a second end of the second conductor; 
 a ground plane, connected to a second end of the third conductor; and 
 a bandwidth adjustment portion coupled to an intermediate portion of the third conductor to form an additional path to the ground plane therefrom, said bandwidth adjustment portion including at least two capacitors connected in series, respective ends of the bandwidth adjustment portion being directly connected to the intermediate portion of the third conductor and the ground plane. 
 
     
     
       2. The broadband antenna according to  claim 1 , wherein the second conductor and the third conductor are approximately disposed in parallel. 
     
     
       3. The broadband antenna according to  claim 1 , wherein the second conductor and the third conductor are disposed perpendicular to the first conductor. 
     
     
       4. The broadband antenna according to  claim 1 , wherein the antenna body, the ground plane, the feed-in point, and the bandwidth adjustment portion are disposed on a surface of a substrate. 
     
     
       5. The broadband antenna according to  claim 4 , further comprising another ground plane disposed on another surface of the substrate. 
     
     
       6. A broadband antenna, comprising:
 at least one ground plane; 
 an antenna body formed by a plurality of conductor sections, a first of the conductor sections terminating at an open first end, and a second of the conductor sections extending from a second end of the first conductor section, said second conductor section having an end thereof connected to the ground plane; 
 a feed-in point defined on the antenna body; and, 
 a bandwidth adjustment portion coupled to an intermediate portion of the second conductor section to form an additional path to the ground plane therefrom, said bandwidth adjustment portion including at least one capacitor, respective ends of the bandwidth adjustment portion being directly connected to the intermediate portion of the second conductor section and the ground plane. 
 
     
     
       7. The broadband antenna according to  claim 6 , wherein the bandwidth adjustment portion comprises a plurality of capacitors. 
     
     
       8. The broadband antenna according to  claim 7 , wherein the bandwidth adjustment portion comprises two capacitors connected in series. 
     
     
       9. The broadband antenna according to  claim 6 , wherein the first conductor section is formed by a serpentine metal wire. 
     
     
       10. The broadband antenna according to  claim 6 , wherein the antenna body, the ground plane, the feed-in point, and the bandwidth adjustment portion are disposed on a surface of a substrate. 
     
     
       11. The broadband antenna according to  claim 10 , further comprising a second ground plane disposed on opposite surface of the substrate.